The present invention relates to vertical pole or tree climbers that are commonly used by utility workers and loggers. These climbers generally comprise hooks that form stirrups that extend up the side of one's legs and include a pointed spur or gaff to allow the person to climb up vertical wooden poles and trees. The climbers are generally strapped to the persons calf and foot by a pair of straps. A major problem that has remained unsolved in the use of these climbers is their inherent conductivity due to the metal used within the hooks and straps. If a gaff penetrates an insulated electrical line or the hook or strap buckle comes into contact with a bare electrical line, the pole climber automatically conducts the electricity to the worker's leg causing electrical shock and possible injury.
There has been several attempts to solve this problem with redesigned pole climbers. The U.S. Pat. Nos. 1,867,894 to Rush and 1,243,436 to Marshall use a metal hook that is encased by insulating rubber. This design has several disadvantages. One problem is rubber tends to be susceptible to wear which may lead to a short lifespan of these pole climbers which would not be very economical. Another problem is that the rubber covers the spur which makes the entire climber assembly useless once the spur is worn out while traditional climbers have replaceable spurs. Furthermore, generally the dialectric strength of rubber is low relative to other types of materials such as composite resin impregnated materials.
The U.S. Pat. No. 3,297,105 to Lawrence shows a resin impregnated fiberglass stirrup that is rigidly secured to a metal hook and spur. The problem with this design is that the fiberglass skin is only a partial covering of the steel structural section which can still conduct electricity. Also, if the climbers are exposed to a high enough current, the voltage can arc through the fiberglass or conduct through the spur and electrocute the user. Additionally, the fiberglass skin adds many more costly steps to the construction process of the hooks, and the bonding of the fiberglass skin to the metal can be questionable as a safety aspect of the design due to the incompatibility of the two materials. The pole climber designs noted above fail in their attempt to resolve the problem of preventing electrocution of a person using pole climbers.